Field of the Invention
The invention relates to a microelectronic integrated sensor, in which a cantilever is formed, and which in particular has a pillar, which to support the upper layers extends through a void. The invention also relates to a method for producing the sensor.
Such sensors are used for instance to measure acceleration. The cantilever, together with an upper and a lower electrode, acts as a series capacitor circuit, and changes in capacitance are evaluated as a measured variable. Typically, the formerly known cantilevers are anchored in the sensor via springs. The courses of the process in producing the sensor lead to stress, and particularly mechanical stress, however, in the cantilever. If the springs do not relax completely, the cantilever can sag permanently as a result. Moreover, the forces absorbed in the springs can cause incorrect behavior of the cantilever during operation. For mechanically stabilizing these sensors, top closure plates, which as a rule comprise a polysilicon layer, are supported with the aid of oxide pillars. The closure times can also be formed of a metallization and supported with metallizing pillars. In the case of aluminum pillars, however, the problem is that they must be insulated from the lower electrode, for instance by means of a diode. Nevertheless, leakage currents can still occur, which impair the function of the sensor. Oxide pillars can be made only within difficulty, since their embodiment is problematic and is strongly dependent on the etching times.